Purpose: The aim of the study was to ascertain whether experimental
hyperthyroidism changes the neurotrophic activity of 14- and
21-day-predegenerated peripheral nerve grafts towards CNS neurites.
Methods: Hyperthyroidism was induced by subcutaneous injections of T
$_4$
.
Autologous peripheral nerve grafts were implanted into the hippocampus of both
euthyrotic and hyperthyrotic animals 14 or 21 days after sciatic nerve
transection (groups ET14, Et21, Ht14 and Ht21, respectively).
Non-predegenerated grafts were used as a control group (groups EtN adn HtN).
Cells extending their neurites into the grafts were traced with FITC-HRP.
Results: The number of traced cells in individual groups was as follows: EtN
-- 39.4 ± 9.46, Et14 -- 1 ± 0.94, Et21 - 0.6 ± 0.69; HtN -- 95
± 19.46; Ht14 -- 95.94 ± 16.3, Ht21 -- 99.94 ± 7.26.
Conclusions: We found that experimentally induced hyperthyroidism strongly
enhanced the regeneration of injured hippocampal neurites after implantation of
peripheral nerve grafts that were practically inactive in euthyrotic
animals.
